Liquid cooled electromagnetic apparatus



1957 H. P. LUNDSKOW 2,803,764

LIQUID COOLED ELECTROMAGNETIC APPARATUS Filed Jan. 19, 1955 2Sheets-Sheet l INVENTOR. HENRY P. Lunnsxow H. P. LUNDSKOW LIQUID COOLEDELECTROMAGNETIC APPARATUS Aug. 20, 1957 2 Sheets-Sheet 2ailllllilitiflllliln Filed Jan. 19, 1953 INVENTOR.

HENRY P Luuosxow United States Patent O7 LIQUID COOLED ELECTROMAGNETICAPPARATUS Henry P. Lundskow, Kenosha, was, assignor, by mesneassignments, to Eaton Manufacturing Company, Cleveland, Ohio, acorporation of Ohio Application January 19, 1953, Serial No. 331,953

9 Claims. (Cl. 310-93) This invention relates to electromagneticclutches and the like and more particularly to liquid cooled eddycurrent clutches and dynamometers.

In the liquid cooling of eddy current clutches and dynamometers whereinthe cooling liquid is circulated directly to the eddy current surfacesof said mechanisms, undesirable oscillation, hydraulic surge orfluctuation of the mechanism occurs due to liquid slugging, turbulenceor uneven distribution of the liquid over the eddy current surfaces ofthe mechanism. This condition can be remedied by introducing a smallamount of air or non-explosive gas to the liquid to be circulated overthe eddy current surfaces of the mechanism for the cooling thereof.

Among the principal objects of the invention is the provision of eddycurrent clutches or dynamometers hav ing liquid circulated through theeddy current flux gap thereof for cooling purposes, in which:

a. Air is introduced into the cooling liquid effective to produce aneffervescent condition of the liquid whereby it may be evenlydistributed across the eddy current surfaces;

b. Oscillation or fluctuation due to water surging, turbulence or unevendistribution of the cooling liquid is practically eliminated;

c. The cooling liquid is aerated and as such as effectivglydistributedover and wets the eddy current surfaces; an

d. Air or non-explosive gas is added to the cooling liquid for reducingdisturbance in speed of the clutches or dynamometers.

Other objects and advantages of the invention will appear from thefollowing description taken in connection with the drawings forming apart of the specification; and in which:

Fig. 1 is a vertical cross-sectional view of a dynamometer embodying theinvention; and

Fig. 2 is a fragmentary partly cross-sectional partly broken away viewof the liquid and air or non-explosive gas coupling for the dynamometerof Fig. 1.

Fig. 3 is a crosssectional partly broken away view taken substantiallyalong lines 33 of Fig. 1.

It has been determined that by the addition of air or non-explosive gasto the liquid to be circulated through the eddy current flux gap ofdynamometers, driving and absorbing dynamometers, and variable speedclutches for the cooling thereof, undesirable oscillations orfluctuations due to liquid slugging, turbulence or uneven distributionof the cooling liquid is practically eliminated thereby providing forthe steadier and more eflicient operation of the mechanism.

Through the addition of air or non-explosive gas to the cooling liquid,an effervescent or aerated condition is produced permitting of a uniformdistribution of the cooling ice liquid, an effective filling of themagnetic flux gap and an effective wetting of the eddy current surfacesadjacent the gap.

Referring to the drawings for more specific details of the invention 10represents generally a dynamometer, a rocking stator 12 of which issupported upon axially spaced bearings 14 mounted on supportingpedestals 16. Stator 12 comprises end closure plates 18 and 20respectively having an internally interdigitated toothed cylinder 22bolted therebetween, said cylinder being made of suitable magneticmaterial. I

Axially opposite extended sleeve portions 24 and 26 of the respectiveplates 18 and 20 are arranged internally of the spaced bearings 14 forrocking motion support thereon. Bearings 28 are mounted in axiallyspaced relation internally of the respective sleeve portions 24 and 26of plates 18 and 20 and in turn support thereon a rotary twopart driveshaft 30 which passes through water seals 32. Seals 32 are spaced fromone another and are supported in annular flanged members 34 bolted tothe respective end closure plates 18 and 20 axially inwardly of therespective sleeve portions 24 and 26 thereof. As such a liquid tightchamber 36 is provided internally of the end closure plates 18 and 20and cylinder 22, the purpose of which will hereinafter appear.

Shaft 30 axially intermediate the seals 32 is bolted to the hub 38 of asupporting spider 40 of rotor 42. An eddy current cylindrical drum 44 isfixedly secured to the outer periphery of spider 40. Drum 44 has asmooth external cylindrical surface and is made of a suitable magneticmaterial.

Cylinder 22 of stator 12 is composite in structure and includes an outerring 46, internal oppositely disposed rings 48 bolted to ring 46 andrespectively to the end closure plates 18 and 20. An annular space 50 isprovided axially between portions of rings 48 within which an annularelectromagnetic coil 52 is securely arranged, supplied electric currentfrom a source, not shown. Each of the rings 48 includes on its innerperiphery a series of circumferentially spaced axially extended polarteeth 54 arranged in interdigitated relation to the teeth on the otherring 48 radially internally of the coil 52. The teeth 54 are provided ontheir inner diameter with curved surfaces Which lie in a commoncylindrical surface spaced a predetermined amount from the externalcylindrical surface of drum 44. This space A designates the magneticflux gap between the rotor and stator of the dynamometer. The combinedaxial width of the polar teeth 54 is substantially identical with theaxial width of the drum 44 whereby eddy currents are confined to radialflow therebetween.

The portions of rings 48 bolted to end cover plates 18 and 20 each havea greater diameter than the cylindrical surfaces of polar teeth 54 suchthat by reason of provision of cooperative axially extended flanges 56and 58 respectively on spider 40 and end cover plate 20 a confinedannular chamber 60 is provided to one side of drum 44 :and throughstructural cooperation between an axially extended portion 62 of endcover plate 18 and a portion of drum 44 a chamber 64 is provided on theopposite side of drum 44 from chamber 60. Chambers 60 and 64 communicatewith space A at opposite ends thereof.

Liquid for cooling the dynamometer effective to communicate with thespace A between the cylindrical surfaces of the stator and rotor is fedby way of liquid conduits 66 extending through the rings 48 into thespace between the interdigitated teeth 54 from whence it communicateswith space A. Conduits 66 are supplied cooling liquid by way of suitablepiping including conduits 68, T connection 7% nipple connection 72, Tconnection 74 and conduit '76 with conduit 76 being connected to thesource of cooling liquid. As shown more clearly in Figure 2 one branch73 of T connection 74 is connected to nipple '72 and another branch 80is connected to conduit 76, the third branch 82 is connected by angularnipple 84 and suitable conduit as to an air or non-explosive gas supply.A sleeve 88 of smaller diameter than the inner diameter of T connection7 is connected at one end to nipple 84 with the sleeve extending betweenbranches 82 and 78 of the T connection 7% and bridging the openingthrough branch 80 such that air as admitted, through sleeve 88, flowsdownstream in the direction of flow with the liquid supplied by conduit76.

The bottom of chambers 64) and 64 provide respective sumps 90 and 92 towhich are connected outlet conduits 94 extending through the portions ofrings 48 bolted to the respective end closure plates 18 and 2t) intocommunication with the sumps 9t) and 92. Conduit 94 serve to drain thecooling liquid delivered to the dynamometer for its subsequent deliveryhandling either for re-use or outright disposal.

End rings 96 arranged on the external opposite axial ends of teeth 54serve to confine the liquid which is fed to the dynamometer for passagethrough space A for effectively cooling the dynamometer. A smallclearance is provided between the internal periphery of the rings andexternal periphery of the drum whereby the liquid discharged from thespace A can be effectively controlled. Rings 96 as seen in Figs. 1 and 3of the drawings have openings provided therein adjacent the sumps 9t)and 92 permitting the liquid, discharged from space A into chambers 6%and 64, to pass easily and quickly to the sumps 90 and 92. A pair ofoppositely angularly disposed baflles 1% are arranged in chord manner inthe teeth portion of rings 48 as shown by Figs. 1 and 3 and serve toseparate sumps 9t? and 92 from the confined liquid chamber 1G2 providedby end rings 96, the rings 48 and the drum thereby necessitating theflow of liquid between the inner periphery of end rings 96 and externalperiphery of drum 4-4.

By so confining the liquid to flow in chamber 102 and space A an entirefilling of effervescent liquid between the teeth and external surface ofthe drum is possible whereby the effervescent liquid is equallydistributed across the entire surface of the drum.

By providing for the introduction of air or non-explosive gas into thecooling liquid an effervescent or aerated condition is produced suchthat this effervescent liquid in being fed into the chambers 6t? and 64at the top of the dynamometer is drawn through the eddy'current iiux gapunder the action of relative rotation occurring between the cooperativeeddy current surfaces of the stator and rotor. With the coil 52energized and with the shaft being rotated the heat generated due toeddy current flow between the rotor and stator as they are rotatedrelative to one another is extracted therefrom by the effervescentliquid passing through space A. By reason of the effervescence of theliquid, at more uniform distribution and effective wetting action of theliquid occurs across the cooperative eddycurrent surfaces of the statorand rotor and between the interdigitated polar teeth 54. In so beinguniformly distributed the cooling liquid serves to maintain a uniformbalance or cushion effect between the stator and rotor such that auniform and steady condition of operation results at the output of thedynamometer thereby accounting for virtually eliminating undesirableoscillation or fluctuation that might otherwise occur.

The effervescent liquid delivered to the chambers 56 and 58 upon servingits cooling function passes to sumps 90 and 92 from where it is drainedfrom the dynamometer.

Although the invention has been described specifically both as to theform of liquid aerating means and the mechanism to which applied, it isreadily conceivable that the basic premise taught is applicable to anyof several like electro-magnetic mechanisms wherein the cooling thereofis accomplished by the introduction of the cooling liquid into the fluxflow path between relatively rotatable parts thereof and further thatany means capable of producing an effervescent condition in the coolingliquid can be utilized without departing from the scope of theinvention. Accordingly, the invention is to be interpreted in the lightof the aforesaid recitations as evidenced by the appended claims whereinthe term clutch is to be understood as embracing mechanisms such asbrakes, clutches and dynamometers.

What I claim is:

1. In mechanism of the class described, a magnetic stator member, amagnetic rotor member, an annular coil carried by one of the members,end members secured to the stator member and forming a liquid tightcompartment around the rotor member, a plurality of interdigitated,axially spaced polar teeth on one member spaced from a cooperativeportion of the other member and ring means arranged at the remote endsof said axially spaced teeth and partially enclosing the space betweensaid teeth and said cooperative portion of said other member, said coilproviding a magnetic flux field passing through the rotor and statorbetween the polar teeth on the one member and the cooperative portion ofthe other member, means introducing effervescent cooling liquid forcirculation in the liquid tight compartment and between the polar teethon the one member and the cooperative portion of the other member, andsaid end ring means restricting the flow of cooling liquid away from thespace between said polar teeth and said cooperative portion of saidother member.

2. In mechanism according to claim 1 wherein the polar teeth arearranged on the stator at the inner periphery thereof and wherein thecooperative portion of the rotor is radially spaced therefrom.

3. In mechanism according to claim 2 wherein the cooperative portion ofthe rotor presents a cylindrical surface to the polar teeth and whereinthe coil is arranged on the stator.

4. In a mechanism of the class described, a cylindrical magnetic member,a magnetic rotor rotatable relative to said cylindrical member, fluxconcentrating teeth arranged in interdigitated array and extendinginwardly from said cylindrical member, an annular coil carried in saidcylindrical member and providing a flux field interlinking saidcylindrical member and said rotor and passing through said teeth,enclosure means on said cylindrical member cooperating with said rotorto form a liquid tight compartment, bafile means extending betweenadjacent flux concentrating teeth, end ring means provided at the remoteends of said teeth, means for introducing effervescent liquid throughsaid cylindrical member between said teeth of said cylindrical member,and said baffle means and said end ring means being arranged to directthe flow :of liquid radially between said teeth and the peripheralsurface of said rotor.

5. A mechanism according to claim 4 wherein the inlet means are disposedto introduce the liquid into the compartment at axial opposite ends ofthe spaced cooperative portions of the members.

6. A mechanism according to claim 4 wherein means are provided formixing air or non-explosive gas with the liquid to be introduced intothe compartment.

7. A mechanism according to claim 4 wherein one of the members is astator and the other a rotor.

8. A mechanism according to claim 7 wherein the stator is cylindricaland includes end closure members in enclosed relation to the rotor withthe compartment therebetween.

9. A mechanism according to claim 8, wherein annu' lar chambers areprovided on opposite axial ends of the space between the cooperativeportions of the stator and References Cited in the file of this patentUNITED STATES PATENTS Breeze Oct. 27, 1914 Doyle May 31, 1927 6 WintherIan. 9, 1945 Winther Jan. 16, 1945 Anderson Dec. 17, 1946 Hugin Mar. 18,1947 FOREIGN PATENTS Great Britain Sept. 24, 1936 Great Britain May 20,1946

